1. Technical Field
This invention relates to processes for preparing 1H-imidazo[4,5-c]quinolin-4-amines and to intermediates for use in preparing 1H-imidazo[4,5-c]quinolin-4-amines.
2. Description of the Related Art
Certain antiviral immunomodulator 1H-imidazo[4,5-c]quinolin4-amines and methods for their preparation are known and disclosed. For example U.S. Pat. Nos. 4,689,338 and 4,929,624 (Gerster) disclose a method involving the step of heating the corresponding 4-chloro compound in the presence of ammonium hydroxide or ammonia under pressure to provide the 4-amino compound. U.S. Pat. No. 4,988,815 (Andre) discloses a process involving aminatio or the 4-position of a 3-nitro-1,4-dichloroquinoline. This process too involves as a final step the reaction of ammonia with a 4-chloro-1H-imidazo[4,5-c]quinoline.
Milder methods have been used in order to introduce the 4-amino group of 1H-imidazo[4,5-c]quinolin-4-amines. U.S. Pat. No. 5,175,296 (Gerster) discloses a process involving the reaction of a 1H-imidazo[4,5-c]quinolinc 5N-oxide with an organic isocyanate and hydrolyzing the product to provide the 4-amino compound. U.S. Pat. No. 5,367,076 (Gerster) discloses a process involving the reaction of a 1H-imidazo[4,5-c]quinoline 5N-oxide with an acylatitig agent and reacting the product with an aminating agent to provide the 4-amino compound. U.S. Pat. No. 5,395,937 (Nikolaides) discloses a process involving amination of the 4-position of a 3-nitroquinoline-2,4-disulfonate with a substituted amine. The final step of the process involves hydrogenolysis to provide the 4-amino compound.
This invention provides a process for preparing a 1H-imidazo[4,5-c]quinolin-4-amine comprising the steps of:
(i) providing a tetrazolo[1,5-a]quinolin-5-ol;
(ii) nitrating the compound from step (i) to provide a 4-nitrotetrazolo[1,5-a]quinolin-5-ol;
(iii) sulfonylating the compound from step (ii) to provide a 4-nitrotetrazolo[1,5-a]quinolin-5-sulfonate;
(iv) reacting the compound from step (iii) with an amine to provide a (5-substituted)-4-nitrotetrazolo[1,5-a]quinolin-5-amine;
(v) reducing the compound from step (iv) to provide a (5-substituted)tetrazolo[1,5-a]quinolin-4,5-diamine;
(vi) reacting the compound from step (v) with a carboxylic acid or an equivalent thereof to provide a (5-substituted) (6-substituted) 6H-imidazo[4,5-c]tetrazolo[1,5-a]quinoline;
(vii) reacting the compound from step (vi) with triphenylphosphine to provide a (1-substituted) (2-substituted) N-triphenylphosplinyl-1H-imidazo[4,5-c]quinolin-4-amilne;
(viii) hydrolyzing the compound from step (vii) to provide a (1-substituted) (2-substituted) 1H-imidazo[4,5-c]quinolin-4-amine; and
(xi) isolating the (1-substituted) (2-substituted) 1H-iinidazo[4,5-c]quinolin-4-amine or a pharmaceutically acceptable addition salt thereof.
This invention also provides a process for preparing a 1H-imidazo[4,5-c]quinolin-4-amine comprising the steps of:
(i) providing a (4-substituted) amino-2-chloro-3-nitroquinoline;
(ii) reacting the compound from step (i) with sodium azide to provide (5-substituted)-4-nitrotetrazolo[1,5-a]quinolin-5-amine;
(iii) reducing the compound from step (ii) to provide a (5-substituted)tetrazolo[1,5-a]quinolin-4,5-diamine;
(iv) reacting th compound from step (iii) with a carboxylic acid or an equivalent thereof to provide a (5-substituted) (6-substituted) 6H-imnidazo[4,5-c]tetrazolo[1,5-a]quinoline;
(v) reacting the compound from step (iv) with triphienylphosphine to provide a (1-substituted) (2-substituted) N-triphenylphosphinyl-1H-imidazo[4,5-c]quinolin-4-amine;
(vi) hydrolyzing the compound from step (v) to provide a (1-substituted) (2-substituted) 1H-imidazo[4,5-c]quinolin-4-amine; and
(vii) isolating the (1-substituted) (2-substituted) 1H-imidazo[4,5-c]quinolin-4-amine or a pharmaceutically acceptable addition salt thereof.
This invention also provides a process for preparing a 1H-imidazo[4,5-c]quinolin-4-amine comprising the steps of:
(i) providing a (1-substituted) (2-substituted) 4-chloro-1H-imidazo[4,5-c]quinoline;
(ii) reacting the compound from step (i) with hydrazine to provide a (1-substituted) (2-substituted) 4-hydrazino-1H-imidazo[4,5-c]quinoline;
(iii) reacting the compound from step (ii) with sodiumi nitrite to provide a (5-substituted) (6-substituted) 6H-imidazo[4,5-c]tetrazolo[1,5-a]quinoline;
(iv) reacting the compound from step (iii) with triphenylpliosphiine to provide a (1-substituted) (2-substituted) N-triphenylphosphinyl-1H-imidazo[4,5-c]quinolin-4-amine;
(v) hydrolyzing.the compound from step (iv) to provide a (1-substituted) (2-substituted) 1H-imidazo[4,5-c]quinolin-4-amine; and
(vi) isolating the (1-substituted) (2-substituted) 1H-imidazo[4,5-c]quinolin-4-amine or a pharmaceutically acceptable addition salt thereof.
This invention also provides processes involving certain of the various individual steps set forth above, and combinations of such steps.
In another aspect this invention also provides 4-nitrotetrazolo[1,5-a]quinolin-5-ols, 4-nitrotetrazolo[1,5-a]quinoline-5-sulfonates, (5-substituted)-4-nitrotetrazolo[1,5-a]quinolin-5-amines, (5-substituted)tetrazolo[1,5-a]quinolin-4,5-diamines, (5-substituted) (6-substituted) 6H-imidazo[4,5-c]tetrazolo[1,5-a]quinolines, (1-stituted) (2-substituted) 4-hydrazino-1H-imidazo[4,5-c]quinolines, and (1-substituted) (2-substituted) N-triphenylphosphinyl-1H-imidazo[4,5-c]quinolin-4-amines.
Substituents designated parenthetically herein indicate that the substituent is optionally present, e.g., a 4-(substituted) amino compound contains either an unsubstituted 4-amino group or a substituted 4-amino group.
Reaction Scheme I illustrates processes of the invention and the preparation of compounds of the invention. The unsubstituted compound of Formula I is a known compound and other compounds of Formula I can be prepared by methods known to those skilled in the art and disclosed, e.g., in Chemistry of Heterocyclic Compounds (English Edition), 1981, 16, (12), 1286-1288 (Zyryanov). 
In step (1) of Reaction Scheme I a 4-nitrotetrazolo[1,5-a]quinolin-5-ol of Formula II is provided by nitrating a tetrazolo[1,5-a]quinolin-5-ol of Formula I. Conventional conditions for such reactions are well known. Preferred conditions in the instance where R is hydrogen involve heating in acetic acid in the presence of nitric acid. Preferred conditions in other instances will depend upon the particular tetrazolo[1,5-a]quinolin-5xe2x80x2-ol used, and those skilled in the art will be able to select suitable conditions. The product can be isolated from the reaction mixture using conventional methods.
In step (2) of Reaction Scheme I a 4-nitrotetraozolo[1,5-a]quinolin-5-sulfonate of Formula III is provided by reacting a 4-nitrotetrazolo[1,5-a]quinolin-5-ol of Formula II with a sulfonyl halide or preferably a sulfonic anhydride. Suitable sulfonyl halides include alkylsulfonyl halides such as methanesulfonyl chloride and trifluoromethanesulfonyl chloride, and arylsulfonyl halides such as benzenesulfonyl chloride, p-bromobenzenesulfonyl chloride and p-toluenesulfonyl chloride. Suitable sulfonic anhydrides include those corresponding to the above-mentioned sulfonyl halides. Sulfonic anhydrides are preferred in view of the fact that the sulfonate anion generated as a by-product of the reaction is a relatively poor nucleophile and as such does not give rise to undesired side products such as those in which the nitro group is displaced. A particularly preferred sulfonic anhydride is trifluoromethanesulfonic anhydride.
The reaction is preferably carried out by combining a compound of Formula II with a base, preferably an excess of a tertiary amine base (e.g., a trialkylamine base such as triethylamine) in a suitable solvent such as dichloromethane and then adding the sulfonyl halide or sulfonic anhydride. The addition is preferably carried out in a controlled fashion (e.g., dropwise) and at a reduced temperature (e.g., about 0xc2x0 C.). The product can be isolated by conventional methods or it can be carried on without isolation as described below in connection with step (3).
In step (3) of Reaction Scheme I a (5-substituted) 4-nitrotetrazolo[1,5-a]quinollin-5-amine of Formula IV is provided by reacting a 4-nitrotetrazolo[1,5-a]quinolin-5-sulfonate of Formula III with an amine, preferably in the presence of an excess of an amine base in a solvent such as dichloromethane. Suitable amines include ammonia and preferably primary amines. Primary amines provide 5-substituted amino compounds of Formula IV wherein the amino substituent is represented by R1. Particularly prceferred amines include isobutylamine and 2-aminomethyl-2-propanol.
The reaction can be carried out by adding an excess of amine to the reaction mixture resulting from Step (2). The reaction can also be carried out by adding an excess of amine to a solution of the compound of Formula III in a solvent such as dichloromethane. As the sulfonate is a relatively facile leaving group the reaction can be run at ambient temperature. The product can be isolated from the reaction mixture using conventional methods.
In step (4) of Reaction Scheme I a (5-substituted)tetrazolo[1,5-a]quinolin-4,5-diamine of Formula V is provided by reducing a (5-substituted) 4-nitrotetrazolo[1,5-a]quinolin-5amine of Formula IV. Methods for such reduction are well know to those skilled in the art. Preferably the reduction is carried out using a conventional heterogeneous hydrogenation catalyst such as platinum on carbon or palladium on carbon. The reduction can be conveniently carried out on a Paar apparatus in a solvent such as ethanol. The product can be isolated from the reaction mixture using conventional methods.
In step (5) of Reaction Scheme I a (5-substituted) (6-substituted) 6H-imidazo[4,5-c]teirazolo[1,5-a]quinoline ofFormula VI is provided by reacting a (5-substituted)tetrazolo[1,5-a]quinolin-4,5-diamine of Formula V with a carboxylic acid or an equivalent thereof. Suitable equivalents to carboxylic acid include acid halides, orthoesters, and 1,1-dialkoxyalkyl alkanoates. The carboxylic acid or equivalent is selected such that it will give rise to the desired 6-substituent in the compound of Formula VI wherein the 6-substituent is designated R2 (e.g., acetyl chloride will give rise to a compound where R2 is methyl). The reaction can be run in the absence of solvent or preferably in an inert solvent in the presence of a carboxylic acid or equivalent thereof with sufficient heating to drive off any alcohol or water formed as a side product of the reaction. The product can be isolated from the reaction mixture using conventional methods.
In step (6) of Reaction Scheme I a (1-substituted) (2-substituted) N-triphenylpliosphinyl-1H-imidazo[4,5-c]quinolin-4-aminc of Formula VII is provided by reacting a (5-substituted) (6-sulbstituted) 6H-imidazo[4,5-c]tetrazolo[1,5-]quinoline of Formula VI with triphenylphosphine. The reaction can be carried out by combining a compound of Formula VI with triphenylphosphine in a suitable solvent such as 1,2-dichlorobenzene and heating. The product can be isolated from the reaction mixture using conventional methods.
In step (7) of Reaction Scheme I a (1-substituted) (2-substituted) 1H-imidazo[4,5-c]quinoline-4-amine of Formula VIII is provided by hydrolysis of a (1-substituted) (2-substituted) N-triphenylphosphinyl-1H-imidazo[4,5-c]quinolin-4-amine of Formula VII. Such a reaction can be carried out by general methods well known to those skilled in the art (e.g., by heating in a lower alkanol in the presence of an acid). The product can be isolated from the reaction mixture by conventional means.
In Reaction Scheme I, Rxe2x80x2 can be any group that can be incorporated into a sulfonyl halide or a sulfonic anhydride. Alkyl (e.g., methyl), haloalkyl including perfluoroalkyl (e.g., trifluoromethyl) and aryl (e.g., phenyl, halophenyl and tolyl) are all suitable.
Reaction Scheme II illustrates processes of the invention and the preparation of comrpounds of the invention. Compounds of Formula IX and methods for their preparation are known and disclosed, e.g. in U.S. Pat. No. 4,988,815 (Andre), and U.S. Pat. No. 5,268,376 (Gerster), both patents being incorporated herein by reference. 
In step (1) of Reaction Scheme II a (5-substituted) 4-nitrotetrazolo[1,5-a]quinolin-5-amine of Formula IV is provided by reacting a (4-substituted) amino-2-chloro-3-nitroquinoline of Formula IX with sodium azide. The reaction can be carried out by combining the compound of Formula IX with sodium azide in a suitable solvent such as N,N-dimethylformamide and heating (about 50xc2x0 C.). The product can be isolated from the reaction mixture using conventional methods.
Steps (2), (3), (4) and (5) of Reaction Scheme II can be carried out in the same manner as steps (4), (5), (6) and (7) of Reaction Scheme I respectively.
Reaction Scheme III illustrates processes of the invention and the preparation of compounds of the invention. Compounds of Formula X and methods. for their preparation are known and disclosed, e.g., in European Patent Application 90.301776.3, U.S. Pat. No. 4,689,338 (Gerster), U.S. Pat. No. 4,698,348 (Gerster), U.S. Pat. No. 4,929,625 (Gerster), U.S. Pat. No. 4,988,815 (Andre), U.S. Pat. No. 5,268,376 (Gerster), and U.S. Pat. No. 5,389,640 (Gerster) all six patents being incorporated herein by reference. 
In step (1) of Reaction Scheme III a (1-substituted) (2-substituted) 4-hydrazino-1H-imidazo[4,5-c]quinoline of Formula XI is provided by reacting a (1-substituted) (2-substituted) 4-chloro-1H-imidazo[4,5-c]quinoline of Formula X with hydrazine. The reaction can be carried out by combining a compound of Formula X with an excess of hydrazine and heating if necessary. The product can be isolated from the reaction mixture using conventional methods.
In step (2) of Reaction Scheme III a (5-substituted) (6-substituted) 6H-imidazo[4,5-c]tetrazolo[1,5-a]quinoline of Formula VI is provided by reacting a (1-substituted) (2-substituted) 4-hydrazino-1H-imidazo[4,5-c]quinoline of Formula XI with sodium nitrite. The reaction can be.carried out by combining the compound of Formula XI with sodium nitrite in a suitable solvent (e.g., water) in the presence of an acid (e.g., acetic acid). The product can be isolated from the reaction mixture using conventional methods.
Steps (3) and (4) of Reaction Scheme III can be carried out in the same manner as steps (6) and (7) of Reaction Scheme I respectively.
The compounds of Formula VIII can be used in the form of acid addition salts such as hydrochlorides, dilhydrogen sulfates, trihydrogen phosphates, hydrogen nitrates, metliane Sulfonates and salts of other pharmaceutically acceptable acids. Pharmaceutically acceptable acid addition salts of Formula VIII are generally prepared by reaction of the respective compound with an equiniolar amount of a strong acid, preferably an inorganic acid such as hydrochloric, sulfuric or phosphoric acid or an organic acid such as methanesulfonic acid in a polar solvent. Isolation of the salt is facilitated by the addition of a solvent in which the salt is insoluble (e.g., diethyl ether).
Processes of the invention provide as a final product a 1H-imidazo[4,5-c]quinolin-4-amine, preferred embodiments of which can be represented by Formula VIII.
Preferably the 1H-imidazo[4,5-c]quinolin-4-amine is a compound defined by one of Formulas XXI-XXV below: 
wherein
R11 is selected from the group consisting of alkyl, hydroxyalkyl, acyloxyalkyl, benzyl, (phenyl)ethyl and phenyl, said benzyl, (phenyl)ethyl or phenyl substituent being optionally substituted on the benzene ring by one or two moieties independently selected from the group consisting of alkyl of one to about four carbon atoms, alkoxy of one to about four carbon atoms and halogen, with the proviso that if said benzene ring is substituted by two of said moieties, then said moieties together contain no more than 6 carbon atoms; acylaminoalkyl wherein the alkyl moiety contains two to four carbon aloms; disubstilutcd aniinoalkyl wherein the alkyl moiety contains two to four carbon atoms; morpliolinoalkyl wherein the alkyl moiety contains two to four carbon atoms; R21 is selected from the group consisting of hydrogen, alkyl of one to about eight carbon atoms, benzyl, (phenyl)ethyl and phenyl, the benzyl, (phenyl)ethyl or phenyl substituent being optionally substituted on the benzene ring by one or two moieties independently selected from the group consisting of alkyl of one to about four carbon atoms, alkoxy of one to about four carbon atoms and halogen, with the proviso that when the benzene ring is substituted by two of said moieties, then the moieties together contain no more than 6 carbon atoms; and each Rxcex9 is independently selected from the group consisting of alkoxy of one to about four carbon atoms, halogen and alkyl of one to about four carbon atoms, and n is an integer from 0 to 2, with the proviso that if n is 2, then said Rxcex9 groups together contain no more than 6 carbon atoms; 
wherein
R12 is selected from the group consisting of straight chain or branched chain alkenyl containing 2 to about 10 carbon atoms and substituted straight chain or branched chain alkenyl containing 2 to about 10 carbon atoms, wherein the substituent is selected from the group consisting of straight chain or branched chain alkyl containing 1 to about 4 carbon atoms and cycloalkyl containing 3 to about 6 carbon atoms; and cycloalkyl containing 3 to about 6 carbon atoms substituted by straight chain or branched chain alkyl containing 1 to about 4 carbon atoms; and
R22 is selected from the group consisting of hydrogen, straight chain or branched chain alkyl containing one to about eight carbon atoms, benzyl, (phenyl)ethyl and, phenyl, the benzyl, (phenyl)ethyl or phenyl substituent being optionally substituted on the benzene ring by one or two moieties independently selected from the group consisting of straight chain or branched chain alkyl containing one to about four carbon atoms, straight chain or branched chain alkoxy containing one to about four carbon atoms, and halogen, with the proviso that when the benzene ring is substituted by two such moieties, then the moieties together contain no more than 6 carbon atoms; and
each RB is independently selected from the group consisting of straight chain or branched chain alkoxy containing one to about four carbon atoms, halogen, and straight chain or branched chain alkyl containing one to about four carbon atoms, and n is an integer from zero to 2, with the proviso that if n is 2, then said RB groups together contain no more than 6 carbon atoms; 
wherein
R23 is selected from the group consisting of hydrogen, straight chain or branched chain alkyl of one to about eight carbon atoms, benzyl, (phenyl)ethyl and phenyl, the benzyl, (phenyl)ethyl or phenyl substituent being optionally substituted on the benzene ring by one or two moieties independently selected from the group consisting of straight chain or branched chain alkyl of one to about four carbon atoms, straight chain or branched chain alkoxy of one to about four carbon atoms, and halogen, with the proviso that when the benzene ring is substituted by two such moieties, then the moictics together contain no more than 6 carbon atoms; and
each RC is independently selected from the group consisting of straight chain or branched chain alkoxy of one to about four carbon atoms, halogen, and straight chain or branched chain alkyl of one to about four carbon atoms, and n is an integer from zero to 2, with the proviso that if n is 2, then said RC groups together contain no more than 6 carbon atoms; 
wherein R14 is xe2x80x94CHRxRy 
wherein
Ry is hydrogen or a carbon-carbon bond, with the proviso that when Ry is hydrogen Rx is alkoxy of one to about four carbon atoms, hydroxyalkoxy of one to about four carbon atoms, 1-alkynyl of two to about ten carbon atoms, tetrahydropyranyl, alkoxyalkyl wherein the alkoxy moiety contains one to about four carbon atoms and the alkyl moiety contains one to about four carbon atoms, 2-, 3-, or 4-pyridyl, and with the further proviso that when Ry is a carbon-carbon bond Ry and Rx together form a tetrahydrofuranyl group optionally substituted with one or more substituents independently selected from the group consisting of hydroxy and hydroxyalkyl of one to about four carbon atoms;
R24 is selected from the group consisting of hydrogen, alkyl of one to about four carbon atoms, phenyl, and substituted phenyl wherein the substituent is selected from the group consisting of alkyl of one to about four carbon atoms, alkoxy of one to about four carbon atoms, and halogen; and
RD is selected from the group consisting of hydrogen, straight chain or branched chain alkoxy containing one to about four carbon atoms, halogen, and straight chain or branched chain alkyl containing one to about four carbon atoms; 
wherein
R15 is selected from the group consisting of: hydrogen; straight chain or branched chain alkyl containing one to about ten carbon atoms and substituted straight chain or branched chain alkyl containing one to about ten carbon atoms, wherein the substituent is selected from the group consisting of cycloalkyl containing three to about six carbon atoms and cycloalkyl containing three to about six carbon atoIms substituted by straight chain or branched chain alkyl containing one to about four carbon atoms; straight chain or branched chain alkenyl containing two to about ten carbon atoms and substituted straight chain or branched chain alkenyl containing two to about ten carbon atoms, wherein tile substituent is selected from the group consisting of cycloalkyl containing three to about six carbon atoms and cycloalkyl containing three to about six carbon atoms substituted by straight chain or branched chain alkyl containing one to about four carbon atoms; hydroxyalkyl of one to about six carbon atoms; alkoxyalkyl wherein the alkoxy moiety contains one to about four carbon atoms and the alkyl moiety contains one to about six carbon atoms; acyloxyalkyl wherein the acyloxy moiety is alkanoyloxy of two to about four carbon atoms or benzoyloxy, and tile alkyl moiety contains one to about six carbon atoms; benzyl; (phenyl)ethyl; and phenyl; said benzyl, (phenyl)ethyl or phenyl substituent being optionally substituted on the benzene ring by one or two moieties independently selected from the group consisting of alkyl of one to about four carbon atoms, alkoxy of one to about four carbon atoms, and halogen, with the proviso that when said benzene ring is substituted by two of said moieties, then the moieties together contain no more than six carbon atoms; acylaminoalkyl wherein the alkyl moiety contains two to four carbon atoms; disubstituted aminoalkyl wherein the alkyl moiety contains twoto four carbon atoms; morpholinoalkyl wherein the alkyl moiety contains two to four carbon atoms;
R25 is 
wherein
RS and RT are independently selected from the group consisting of hdrogen, alkyl of one to about four carbon atoms, phenyl, and substituted phenyl wherein the substituent is selected from the group consisting of alkyl of one to about four carbon atoms, alkoxy of one to about four carbon atoms, and halogen;
X is selected from the group consisting of alkoxy containing one to about four carbon atoms, alkoxyalkyl wherein the alkoxy moiety contains one to about four carbon atoms and the alkyl moiety contains one to about four carbon atoms, haloalkyl of one to about four carbon atoms, alkylamido wherein the alkyl group contains one to about four carbon atoms, amino, substituted amino wherein the substituent is alkyl or hydroxyalkyl of one to about four carbon atoms, azido, alkylthio of one to about four carbon atoms; and
RE is selected from the group consisting of hydrogen, straight chain or branched chain alkoxy containing one to about four carbon atoms, halogen, and straight chain or branched chain alkyl containing one to about four carbon atoms;
or a pharmaceutically acceptable salt of any of the foregoing.
The compounds recited above are disclosed and claimed in the several patents noted above in the Summary of the Invention and discussed below.
In instances where n can be zero, one, or two, n is preferably zero or one.
The substituents Rxcex9-R1: above are species embraced by R. The preferred R substituent is hydrogen.
The substituents R11-R15 above are species embraced by R1. The preferred R1 substituents are alkyl of one to about six carbon atoms, hydroxy alkyl wherein the alkyl moiety contains one to about 6 carbon atoms, and arylalkyl wherein the alkyl moiety contains one to about three carbon atoms. Most preferably the R1 substituent is 2-methylpropyl, 2-hydroxy-2-methylpropyl, benzyl or phenylethyl.
The substituents R21-R25 above arc species embraced by R2. The preferred R2 substituciis are hydrogen, alkyl of one to about four carbon atoms, alkoxyalkyl wherein the alkoxy moiety contains one to about four carbon atoms and the alkyl moiety contains one to about four carbon atoms, hydroxyl alkyl wherein the alkyl moiety contains one to about four carbon atoms, haloalkyl wherein the alkyl moiety contains one to about four carbon atoms, and aryloxymethyl. Most preferably the R2 substituent is hydrogen, methyl, ethoxymethyl, or benzyl.
Certain R substituents, R1 substituents, and R2 substiluents will be incompatible with the particular reaction conditions described above in connection with the Reaction Schemes. Those skilled in the art, however, will be able to select alternative conditions under which the several steps can be carried out and/or methods of functional group protection and manipulation that will allow the use of the processes of the invention in the preparation of 1H-imidazo[4,5-c]quinolin-4-amines of diverse structures.
Certain 1H-imidazo[4,5-c]quinolin-4-amines have been disclosed as antiviral agents (see, e.g., European Patent Application 90.301776.3 (Gerster), U.S. Pat. No. 4,689,338 (Gerster), U.S. Pat. No. 4,929,624 (Gerster), U.S. Pat. No. 5,266,575 (Gerster), U.S. Pat. No. 5,268,376 (Gerster), and U.S. Pat. No. 5,389,640 (Gerster) all five patents incorporated herein by reference). Certain of these compounds are also known to induce biosynthesis of cytokines such as interferons, interleukins, and tumor necrosis factor in humans and in mice.